Channeling the Flow

9 January 2016

In the Northumbrian village of Corbridge, a stretch of road has had some white lines removed and some new ones painted.

And it’s causing a stir.

It will surprise few that the reaction from drivers—at least, the reaction reported by the media—has not been positive (though note that some criticise the county council’s approach rather than the lanes per se). We all naturally resist change that is foisted upon us, especially when it appears to be to our detriment.

But it also seems to have divided online discussion among cycling infrastructure advocates. Some have celebrated the scheme; others have been dismayed. So, why the mixed response?

The idea is to channel the flow of motor vehicle users to the central lane, leaving the cycle lanes for those on pedal cycles. When two motor vehicles need to pass head-on, they move into the cycle lanes to do so.

Where the motor traffic flow is overwhelmingly unidirectional, channeling the flow in this way may work reasonably well. Also, where the motor traffic flow is normally bidirectional but very low in volume, it may be tolerable. But where the flow is more significant, the design breaks down: drivers must predominantly drive in the cycle lanes. (And it should go without saying that this design is not compatible with high speeds.)

Arguably, then, if this design is used on roads with any appreciable traffic levels, one effect is to train drivers to drive in cycle lanes. The higher the motor traffic flow, and the lower the pedal cycle flow, the more this is reinforced.

Indeed, once this starts to occur, it’s difficult to see where any benefit lies. Drivers still have to use the near side of the carriageway and move out to safely pass people on bikes, just as with a normal carriageway. The only difference is in the line markings: instead of a central line which tells drivers that they’re on “someone else’s bit of road” when they move across it, there’s a nearside lane line which communicates a suggested position to adopt when passing. It’s a nuance that influences people’s territorial nature, though the effect of it on practical outcomes is a matter of conjecture. (It’s worth noting that the Corbridge treatment is a small improvement over many similar implementations, in that the advisory lanes are allegedly 5ft wide. Most are rather narrower, and suggest closer passing as a result.)

This video gives an excellent demonstration of how the design fails once flows become non-negligible.

So, the treatment is not ideal. But many argue that it is an improvement worth having; it’s better than nothing. Some ask, not unreasonably: How could it be done better?

Defining “better”

Cycling advocacy inevitably boils down to a small number of key aims, and two of these—arguably the main two—are casualty reduction and increased participation. (There is perhaps a thin strand which connects these: fear reduction.)

Whether this treatment achieves the former is debatable: I’ve seen no evidence on the matter and I have doubts that any statistically significant data even exists (which, if so, might itself tell us something), but I confess I’ve not looked. My concern is perhaps more with the latter.

Is this a change which will cause more people to cycle? Looking at the map, this seems an unlikely commuting route: it leads east out of the village into the countryside and to a large dual carriageway, not across the river to the station from which people can commute to Newcastle (which—being 20 miles from Corbridge—is too far for most people to consider cycling to). It forms part of the Hadrian’s Cycleway, so attracts leisure riders, but while people using Sustrans tourist routes may not be the hardy enthusiasts of the sportive or touring ilk, the nature of most Sustrans routes is such that people are likely to be expecting to share space with motor traffic at some points along their journey. Indeed, further up the road there is a ridiculous sight: a National Cycle Network sign mounted on a national speed limit sign.

I am commenting from afar, and those who are familiar with the area may beg to differ, and maybe this actually is providing a perceived benefit to people riding on the road, but it will certainly be interesting to see whether cycling flow has increased in a year’s time.

The thing is, though, that even if this is a slight improvement over the previous layout, that doesn’t necessarily mean it’s better than nothing.

Sounds paradoxical? I’ll explain.

So, what is better?

When the question of “what do you think would be better here?” is raised as a challenge to dissenters of any scheme, it is valid in some respects but it makes a huge and problematic assumption, which is that we should look “here” first.

And this is the crux of the matter: “better than nothing” tends to enter the conversation when we’re already looking at the tree instead of the wood. It’s very easy, once you’re prepared to cycle on the road on a regular basis, to perceive the points which feel the least comfortable. But this is a self-selecting viewpoint, and it results in these parochial, piecemeal adjustments instead of targeted applications of a more circumspect and holistic view of the situation. It is one of the factors which constantly pulls us back to a culture of sharing the carriageway and excluding the people who don’t wish to do so: people who have overcome the more fundamental barriers to cycling will tend to overlook them.

This is why “better than nothing” is often worse than nothing: even if it actually is better in one specific location, it’s a near-certain bet that doing something in a different location is better overall, and thus—in the location in question—the better solution involves doing nothing.

Use the force wisely

As the CTC proudly reports, the change was hard-fought and won by one of its local activists. The CTC is rightly proud of the effort invested by its volunteers, who are both numerous and enthusiastic. And I have great admiration for the tenacity those who can achieve these sort of changes. But this effort and tenacity warrants the direction afforded by a national strategy.

The “Space for Cycling” flag has flown nationally for some time now, and—let us be absolutely clear on this—paint on a carriageway is not Space for Cycling. Organisations like the CTC are in a position to channel the flow of their members’ valuable and finite time and energy into a holistically productive strategy.

Maybe it’s time to channel a little time and energy persuading them to do that.

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Comments

I’ve not encountered one of these schemes myself, but having watched the Norwich video and read a little about other examples, it seems they don’t always work in the Netherlands either, but where they do, it’s because of one key element which has been neglected in the schemes in Norwich and Corbridge: traffic reduction. The Dutch do this on residential streets by filtered permeability and other means, we don’t, and so these schemes won’t work. We’ve applied a specific solution outside its required environment. This might also be the “other location” that would be a better application of resources.

The road would probably be safer if ALL the road markings were removed. There is some evidence which says that the incidence of close-passes is reduced on roads with no markings at all, particularly the centre line. Maybe it’s because motorists have to switch on their brains and ‘negotiate’ with other road users in order to proceed.

A couple of comments on the specifics of the layout, not necessarily the bigger picture. Quoting the Hexam Courant article;

“However, many motorists have branded them a hazard, with others pointing out that the lanes are wide enough to take a parked car, leaving drivers assuming they are confined to the narrower centre of the road.”
Presumably then, if drivers knew these weren’t parking bays for cars but ‘only’ (advisory) cycle lanes they’d happily be driving in them without a care – much safer.

Secondly the Dutch use coloured surfacing in the ‘advisory shoulders?’ I believe they’re called – my understanding being they’re not actually cycle lanes (my copy of CROW is at the office). There’s a report produced for the UK DfT ‘Road Safety Research Report 100 ‘ which suggests this layout, or something very similar, does have a speed reducing effect, but without the colour the effect is reduced. Possibly showing – aside from the other criticisms levelled at it – ‘Dutch style’ isn’t good enough, it’s got to be the Dutch way in its entirety or nothing.

Its interesting speed is referenced alot for these types of scheme in the UK,as I know in Norwich those advisory cycle lanes were added in conjunction with a reduced speed limit on that road, and close to Martlesham in Suffolk, where there is another of these types of advisory cycle lanes which channels traffic to a central position, that again coincided with a reduced speed limit. The council actually documented that one of the objectives to installing it was “…To reduce average traffic speed (to gain compliance with the speed limit)” in fact out of the 4 stated aims for introducing that cycle lane, cycling was only part mentioned as benefitting in 1 of them.

so the intent for these types of advisory lanes, seems less about providing some cycling infrastructure, and more about achieving other aims, reducing traffic,reducing speed etc in effect using the new road layout and cyclists interaction with other vehicles,as speed limiters, or moving speed bumps.

which is why they probably dont work very well as cycling infra, and I certainly dont believe cycling levels have measurably changed on the road near Martlesham, it definitely doesnt feel any different to cycling along a road without the advisory lane being there.

“The council actually documented that one of the objectives to installing it was “…To reduce average traffic speed (to gain compliance with the speed limit)” in fact out of the 4 stated aims for introducing that cycle lane, cycling was only part mentioned as benefitting in 1 of them.”

“The reasons for laying suggestion lanes are the visual narrowing of the carriageway, and the centring of the traffic on the carriageway or a combination of the two. The lanes themselves do not reduce speed, which is why it is advisable to apply this solution on cycle routes always in combination with speed reduction measures”.

(I’d possibly argue that visually narrowing the carriageway doesn’t reduce speeds – but the manual is getting on a bit and later research may confirm or deny it).

It (CROW) also goes on;

“…indicative recommendations can be made:
at an intensity of 400pcu/h, one traffic path is unacceptable”.

This road is used as a cut-through from the University of the West of England to the north Bristol ring road and the M32 motorway, and is the main exit from the Holiday Inn hotel for traffic wanting to head back to the motorway system. It’s a two-way road, marked as a 30 mph speed limit.

A car simply cannot pass another car without going into the cycle lane, and most cars that I have seen just ignore the cycle lane completely and treat the road as an undivided two way road, and i honestly cannot see the point of it unless the council simply wished to tick a “put in cycling infrastructure” box (and of course they’d never do that, would they…?).

“most cars that I have seen just ignore the cycle lane completely and treat the road as an undivided two way road” But (as I commented further down) is that the fault of layout or the drivers (who have seen something unfamiliar and just chosen to ignore it!).

“So the intent for these types of advisory lanes, seems less about providing some cycling infrastructure, and more about achieving other aims.”

The newly-installed protected cycle lane on St George’s Road (here) is another case in point. If it joined up to the (currently substandard) protected cycle lane on the New Kent Road (here), and if it didn’t end abruptly when it reached the junction with Lambeth Road, but carried on instead towards Westminster Bridge, this would be a very decent route. But it doesn’t, and it isn’t.

The wider point, as you make clear, Bez, is that even if a treatment is actually better in one specific location, it’s a near-certain bet that doing something in a different location is better overall. This is why, as Johan Diepens explained, “In planning for cycling, the critical thing is to design your network correctly” (source). Everything else, he said, is trivial.

“The only difference is in the line markings: instead of a central line which tells drivers that they’re on “someone else’s bit of road”…”

How come the median line indicates that, but the cycle lane markings don’t tell drivers they are on “someone else’s bit of road”? The markings are identical! As a driver I would take the new markings to mean that if I need to move out onto the cycle lane (due to cars coming the other way) then I need to be looking very carefully before I do so, driving slower (at a cycling pace) and moving back into the centre of the lane as soon as possible, certainly before I even think about passing a cyclist.

Obviously I wouldn’t rely on other drivers thinking that way, especially when I have the kids on the bike. But I guess the main point is that once you have a steady flow of traffic (or traffic backing up) in both directions, the whole idea breaks down.

How come the median line indicates that, but the cycle lane markings don’t tell drivers they are on “someone else’s bit of road”? The markings are identical!

Because the dominant traffic flow is that of motor vehicles. In the case of the centre line, this acts to reinforce the idea that crossing the line is problematic. In the case of advisory cycle lane, this acts to cause drivers to drive in the cycle lanes by default. Sure, both are territorial markings, but when combined with the actual flow the effect is very different.

But the context in which I meant that remark is actually rather different: it’s to do with how a driver may perceive the limit of space available for someone on a pedal cycle, not so much that available to themselves. It becomes problematic because someone on a bicycle will be thought to be required to stay in the advisory lane, and that provided a driver stays even a whisker insider the central lane then they have done their bit. Both problematic, especially if the cyclist needs to swerve for any reason.

As a driver I would take the new markings to mean that if I need to move out onto the cycle lane (due to cars coming the other way) then I need to be looking very carefully before I do so, driving slower (at a cycling pace) and moving back into the centre of the lane as soon as possible…

Highway Code Rule 140 should make it clear that this is not how you should approach this design (but many people seem not to realise this, seemingly including the person who campaigned for this change). The idea is to remain in the central lane and only use the cycle lanes when necessary (ie to pass oncoming vehicles). This is just one illustration of how the design falls apart when motor traffic is anything other than minimal.

I’m struggling to see the difference between moving into the cycle lane when needed then returning into the centre lane as soon as possible, and only using the cycle lanes to pass oncoming vehicles. Clearly there’s some different interpretation, but what?